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Commit 1e0a5dec authored by Baokun Li's avatar Baokun Li Committed by Greg Kroah-Hartman
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ext4: add two helper functions extent_logical_end() and pa_logical_end() 



commit 43bbddc067883d94de7a43d5756a295439fbe37d upstream.

When we use lstart + len to calculate the end of free extent or prealloc
space, it may exceed the maximum value of 4294967295(0xffffffff) supported
by ext4_lblk_t and cause overflow, which may lead to various problems.

Therefore, we add two helper functions, extent_logical_end() and
pa_logical_end(), to limit the type of end to loff_t, and also convert
lstart to loff_t for calculation to avoid overflow.

Signed-off-by: default avatarBaokun Li <libaokun1@huawei.com>
Reviewed-by: default avatarRitesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20230724121059.11834-2-libaokun1@huawei.com


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Signed-off-by: default avatarBaokun Li <libaokun1@huawei.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c2102ac1

fs/ext4/mballoc.c

+3 −4
Original line number Diff line number Diff line
@@ -3124,7 +3124,7 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac, 


	/* first, let's learn actual file size

	 * given current request is allocated */

	size = ac->ac_o_ex.fe_logical + EXT4_C2B(sbi, ac->ac_o_ex.fe_len);

	size = extent_logical_end(sbi, &ac->ac_o_ex);

	size = size << bsbits;

	if (size < i_size_read(ac->ac_inode))

		size = i_size_read(ac->ac_inode);
@@ -3462,8 +3462,7 @@ ext4_mb_use_preallocated(struct ext4_allocation_context *ac) 
		/* all fields in this condition don't change,

		 * so we can skip locking for them */

		if (ac->ac_o_ex.fe_logical < pa->pa_lstart ||

		    ac->ac_o_ex.fe_logical >= (pa->pa_lstart +

					       EXT4_C2B(sbi, pa->pa_len)))

		    ac->ac_o_ex.fe_logical >= pa_logical_end(sbi, pa))

			continue;



		/* non-extent files can't have physical blocks past 2^32 */
@@ -4234,7 +4233,7 @@ static void ext4_mb_group_or_file(struct ext4_allocation_context *ac) 
	if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))

		return;



	size = ac->ac_o_ex.fe_logical + EXT4_C2B(sbi, ac->ac_o_ex.fe_len);

	size = extent_logical_end(sbi, &ac->ac_o_ex);

	isize = (i_size_read(ac->ac_inode) + ac->ac_sb->s_blocksize - 1)

		>> bsbits;

fs/ext4/mballoc.h

+14 −0
Original line number Diff line number Diff line
@@ -199,6 +199,20 @@ static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb, 
		(fex->fe_start << EXT4_SB(sb)->s_cluster_bits);

}



static inline loff_t extent_logical_end(struct ext4_sb_info *sbi,

					struct ext4_free_extent *fex)

{

	/* Use loff_t to avoid end exceeding ext4_lblk_t max. */

	return (loff_t)fex->fe_logical + EXT4_C2B(sbi, fex->fe_len);

}



static inline loff_t pa_logical_end(struct ext4_sb_info *sbi,

				    struct ext4_prealloc_space *pa)

{

	/* Use loff_t to avoid end exceeding ext4_lblk_t max. */

	return (loff_t)pa->pa_lstart + EXT4_C2B(sbi, pa->pa_len);

}



typedef int (*ext4_mballoc_query_range_fn)(

	struct super_block		*sb,

	ext4_group_t			agno,